'Survival of the sluggish' - study suggests 'lazier' species are less likely to face extinction

Ellen Manning
<em>Study – scientists examined both extinct and living bivalves and gastropods to look at whether metabolic rate can give an idea about extinction (Picture: Getty)</em>
Study – scientists examined both extinct and living bivalves and gastropods to look at whether metabolic rate can give an idea about extinction (Picture: Getty)

Forget survival of the fittest – it seems that survival of the laziest might be the way forward.

According to new research, lazier species with a lower metabolic rate are more likely to survive than their counterparts who use more energy.

A research team based at the University of Kansas studied both fossil and surviving bivalves and gastropods in the Atlantic Ocean, looking at the metabolic rates of 299 species over a period of five million years.

According to their research, published in the Proceedings of the Royal Society B, those with lower daily energy requirements were less likely to become extinct than those with higher metabolic rates.

<em>The team studied fossils as well as living molluscs (Picture: Getty)</em>
The team studied fossils as well as living molluscs (Picture: Getty)

“Maybe in the long term the best evolutionary strategy for animals is to be lassitudinous and sluggish — the lower the metabolic rate, the more likely the species you belong to will survive,” said professor of ecology and evolutionary biology Bruce Lieberman, who co-authored the paper with Kansas University’s Luke Strotz and Julien Kimmig as well as Erin Saupe of Oxford University.

“Instead of ‘survival of the fittest,’ maybe a better metaphor for the history of life is ‘survival of the laziest’ or at least ‘survival of the sluggish.’”

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The researchers think their work could have important implications for forecasting which species may be facing extinction in the face of impending climate change.

Luke Strotz, postdoctoral researcher at KU’s Biodiversity Institute and Natural History Museum and lead author of the paper, said: “We wondered, ‘Could you look at the probability of extinction of a species based on energy uptake by an organism?'”

He went on: “We found a difference for mollusk species that have gone extinct over the past 5 million years and ones that are still around today.

“Those that have gone extinct tend to have higher metabolic rates than those that are still living. Those that have lower energy maintenance requirements seem more likely to survive than those organisms with higher metabolic rates.”

Strotz said the research has produced a “potential predictor of extinction probability”, adding that while metabolic rate isn’t the ‘be-all, end-all’ of extinction, the results suggest that it is a factor in how likely extinction is.

“With a higher metabolic rate, a species is more likely to go extinct. So, it’s another tool in the toolbox. This will increase our understanding of the mechanisms that drive extinction and help us to better determine the likelihood of a species going extinct.”

Strotz said he used mollusks to study the phenomenon of metabolism’s contribution to extinction rates because of the amount of data available about living and extinct species.